Moving seat chair for exercise and rehabilitation

ABSTRACT

A chair with a seat that moves on a curved motion mechanism in an arc relative to a base to provide flexion and extension of the knee when the user swings the seat back and forth. Telescoping structures adjust to fit different size users. A footrest in front of the chair allows the user to push against it with their feet, thus creating the swinging motion.

This application claims benefit of our Provisional Patent Filing,Application #60/691,410, filed Jun. 17, 2005

The present invention relates to a chair that moves in an arc relativeto a base, which is particularly suited for physical therapy use bypatients who have had hip, knee, ankle joint, or leg surgery. It is alsouseful as a strengthening or conditioning device, and for athletes' useto remain limber and warmed up. The user's legs create motion by thefeet pushing against a fixed object, where the center of motion of theseat is nominally fixed at a point above the seat, with the user's bodymoving generally in a plane. Extendable/repositionable tubes form anadjustable frame to accommodate different size users. An adjustableposition footrest provides a structure for the feet to push off of.Resistance to motion may be varied using added mass, a damper, or aspring. The invention is called the Kneeflexer™.

STATEMENT REGARDING FEDERALLY FUNDED RESEARCH

No federal funds were used in the development of this invention

FIELD OF THE INVENTION

The present invention relates to exercise and rehabilitation equipment,and active sitting chairs.

BACKGROUND

The initial challenges that knee injury patients encounter involveregaining flexion and extension of the knee and reduction of swelling. Awidely used approach is for the patient to lie on his/her back withtheir leg strapped into a knee continuous passive motion machine, suchas those provided by Artromot®-E (Flexmate K500 Knee CPM, Artromot® K4and Artromot® K3) and Optiflex (Optiflex³ knee) which guides the kneethrough flexion and extension. Lying on one's back is good early in therehabilitation process, because it elevates the knee to reduce swelling.Also, the passive motion allows users to regain motion with minimaleffort. However, soon after surgery patients are mobile and motion ofthe knee improves venous circulation; an upright posture machine isdesirable for an active patient. This invention eliminates the need forlying on one's back and being strapped to a continuous passive motionmachine by providing a device which will guide the user in practicingflexion and extension technique, yet enable a user to sit upright andextend and flex the knee with minimal assistance. In addition, due tothe center of rotation in relation to the user, more natural flexion andextension of the knee is achieved. Finally, the user's body motion isrestricted to generally one plane, thus eliminating risks associatedwith side-to-side motion of the body relative to the foot.

There are many “active sitting” devices ranging from simple inflatedballs to chairs mounted on top of coil springs that allow a user toplant their feet on the floor and then move their buttocks in variousmotions. Such devices are intended to strengthen a person's coremuscles. They are not, however, appropriate for rehabilitation becausethe body is too weak to maintain itself on these nominally unstabledevices.

Another important area of applicability is keeping athletes limber orwarmed up, particularly between events, when they would otherwise besitting idle waiting for their turn to perform.

The apparatus created by following the criteria set forth is namedKneeflexer. This apparatus consists of three primary components-a base,a curved motion mechanism, and a seat. A stool, ramp, or other structurecan also be used in conjunction with the feet. A user sits in the seatwhile the feet are supported by the floor or a structure in front of thebase and seat. The motion of the seat is guided in an arc by the curvedmotion mechanism whose motion is about an essentially fixed point abovethe plane of the seat. The Kneeflexer provides guided motion so the usercannot lose control and get hurt. This device, due to its structure,also allows the user to use it as a piece of active furniture.

OBJECTS OF THE INVENTION

An object of the present invention, accordingly, is to guide the user inpracticing flexion and extension of the leg joints while sittingupright.

A further object of the invention is to provide a curved motion path fora seat where the center of rotation is above the plane of the seat andis essentially a fixed point.

A further object is to position the user's leg so that the knee(s) canflex and extend through a guided range of motion.

A further object is to support the weight of the user so that nounwanted load is added to the knee.

A further object is the ability to restrict motion to generally oneplane so that the user properly moves the knee.

A further object is to use adjustable structures so that the equipmentcan be adjusted to accommodate different size users.

A further object is that weight can be added to the equipment toincrease resistance to motion.

A further object is that spring(s) can be added to the equipment toincrease resistance to motion.

A further object is that a dashpot (for example, damper, shock absorber)can be added to the equipment to increase resistance to motion.

A still further object is to provide range of motion stops to limit thetravel arc of the seat.

SUMMARY

The Kneeflexer consists of three primary components-a base, a curvedmotion mechanism, and a seat. A footrest, which may be attached to thebase, can also be placed under the feet to change the type of motion thejoint experiences. The curved motion mechanism radius of curvature isgenerally about one meter so its center of rotation is generally at apoint near the head of a typical user, although different radii ofcurvature rails could be used for different size chairs. Thus whenmoving, the user's head does not appreciably translate, and they canmore easily stay focused on a computer monitor, for example, while usingthe device. A user sits in the seat while the feet are supported by thefloor or a ramp or platform or other structure in front of the base andseat. The Kneeflexer also allows the user to use it as a piece of activefurniture for use by healthy people who want to exercise by moving whilesitting, or by athletes who want to remain limber and warmed up betweenevents.

DRAWINGS

The invention will now be described with reference to the accompanyingdrawing in which:

FIG. 1 is an isometric drawing of the structure with attached footsupport;

FIG. 2 is an isometric drawing of the structure without attached footsupport;

FIG. 3 is an isometric drawing of the structure with added resistanceelements;

FIG. 4 is a side drawing of the structure with added resistanceelements;

FIG. 5 is an exploded view isometric of the structure;

FIG. 6 shows a user operating the Kneeflexer with the knee in extension;

FIG. 7 shows a user operating the Kneeflexer with the knee in flexion;

FIG. 8 shows the Kneeflexer in the back position, for knee extension;

FIG. 9 shows the Kneeflexer in the front position, for knee flexion;

FIG. 10 shows the Kneeflexer with an inclined foot support;

FIG. 11 shows a user operating the Kneeflexer with an inclined footsupport.

PREFERRED EMBODIMENT(S) OF THE INVENTION

FIGS. 1 and 2 show preferred embodiments of the invention which is madefrom metal, which the frame of can be extruded as a tube and then cutand bent as is well-known to those skilled in the art of metallicproduct manufacture. The Kneeflexer 1 has a curved bearing rail 4,bottom structure 2 with left and right sides 2 a and 2 b and back side 2c. Structure 3 is attached to structure 19, which in turn is attached tostructure 5, which supports structure 2, which supports the user.Structure 5 acts as a bearing carriage to guide and support the curvedbearing rail 4, at the bottom of structure 2 and it connects tostructure 3 via structure 19. Resistance to motion may be increased byadding mass to sides 2 a, 2 b and/or 2 c; resistance may also beincreased by adding a spring or dashpot between structure 2 andstructure 3. Fastener 6 provides security to lock the structuralelements in a range of positions suitable for all users. It is shown asa pin, but could be a clamp or other fastening device. In addition, FIG.1 shows a foot support structure 9, which is adjustable in height andangular position by extending and rotating tubes, which can be pinned inplace once adjusted, as is common with exercise equipment. The user'sfeet push off the bar.

FIG. 3 shows an isometric view of the invention with added resistanceelements. Structures 10 a and 10 b are resistance elements such assprings or dampers attached to structure 2 and structure 3. Structure 11a, 11 b and 11 c are posts for mass resistance elements 12 (weights)that may be added to resist motion.

FIG. 4 shows a side view of the invention with added resistance elements10 a and 10 b (e.g., springs or elastomer bands); these are attached topost structures 13 a and 13 b on structure 2 and post structure 13 c onstructure 3.

FIG. 5 shows an exploded view of the Kneeflexer 1. Structure 5 supportscurved bearing rail 4 to securely hold structure 2. Structure 19 fitsinto hole 14 on structure 3. Fastener 6 fits into hole 16 a on structure3 and any one of holes 16 b on structure 19. The result is a sturdyadjustable frame and seat assembly.

FIG. 6 shows a user 15 seated in structure 2. The Kneeflexer 1 is in theback position and the knee 7 of user 15 is in extension. The user's foot17 is placed on foot rest, structure 18.

FIG. 7 shows a user 15 seated in structure 2. The Kneeflexer 1 is in thefront position and the knee 7 of user 15 is in flexion.

FIG. 8 shows structure 2 in the back position.

FIG. 9 shows structure 2 in the front position.

FIG. 10 shows Kneeflexer 1 with an inclined foot support 8.

FIG. 11 shows a user 15 seated in structure 2. The foot 17 of the useris placed on an inclined foot support 8. The inclined surface provides acontinually variable elevation that enables the user to easily selectthe desired position for operating the chair.

Not shown is a brake, such as a simple lever, that locks the chair intoposition so it does not move when the user first sits in the chair. Thiswill prevent the chair from moving and startling the user, particularlyfirst-time users. Such brakes are well-known to those skilled in the artof wheelchairs and exercise equipment. In addition, or alternately, pinsor bumpers can be removably attached to structure 2 or other elements ofKneeflexer 1 to limit range of motion.

As an example of the use and benefits of the Kneeflexer, consider thefollowing discussion by one of the inventors, Randy Gelo:

“I am 41 years old, and a full-time karate instructor in my own school(dojo). I teach many children how to use karate as a source of innerpeace and strength. In addition, I teach women's self-defense classesand special defense classes for the local police. When I was 16 I gothurt in a high school football game. Shortly afterwards, a surgeon tookout the cartilage from the outside of my right knee; I had split thecartilage in half. From then until my knee replacement in Sept. 2003 Ihave had four surgeries on the knee. My pain was so bad that the doctorcould not imagine how I could even walk because bone was grinding onbone. My ability to teach karate was in jeopardy because I could nolonger demonstrate moves to my students. That is when I decided to seeka knee replacement.

“After knee replacement surgery, I could not find anything that wouldhelp me to regain flexibility in my knee. Obtaining full extension,which is needed for a normal lifestyle, was a major problem. My knee hadsimply frozen up with less than 30 degrees of flexion. I had to go backfor surgery to have my knee manipulated into full flexion. Afterwards,although I had therapy every day, it did not help much. I had the CPM[prior art, commercially available] machine at my home; I used it everyday for 4-6 hours a day for two months. It made very little differencein the flexion of my knee.

“I also had pool therapy; yet still, I barely got to about 100 degreeflexion by forcing my leg to bend. After the completion of my therapysessions, I had 102 degree bend, but only by forcing the leg to bend. Icould not bend the leg using my own leg muscles. It took months before Icould even ride a stationary bike, nothing seemed to work. The kneewants to enable the leg to bend about 80 degrees while pedaling a bike;I tried forcing the knee with squats and trying to sit on my shins. Thiscreated a lot of pain with no improvement.

“I tried using a yoga ball (a 3 ft. exercise ball). There was nostability and it was dangerous because there was no support when Ireached my limit or end of flexion. A rocking chair worked a little inthe beginning, except it was very limited in the amount of flexion Icould obtain. I was lucky to bend my knee 45 degrees in either a rockeror glider chair.

“Then, in discussions with my co-inventors, we came up with the idea forthe Kneeflexer. It has some resistance, caused by gravity, to help buildstrength with the flexibility. You are relaxed as you use it and you cancontrol the motion with your other leg. The natural swinging (pendulum)motion can be increased ever so slowly to coax the leg into flexion, andthe use of my own leg muscles to create the motion helps to strengthenthem.

“With the prototype Kneeflexer, I first used a chair to prop my feet upas I used the machine. Adjusting the height affects the knee a littledifferently so I started using a step stool. It worked pretty well. Itdid not work my ankles right; I had the hardest time picking my toes upoff the ground (with my foot on the ground). I then built a ramp that isadjustable. It works the ankles and the hips as well as the knee. Thehigher the incline the more the ankle and hip work (both flexion andextension). This combination works the best. Start with your foot nearthe top of the ramp, which works your extension of the knee joint andhamstring muscles in the back of the leg. As you lower the foot closerto the bottom of the ramp, you work on flexion of the knee and the quadmuscles also the ankle joint and calf muscles. I use this position themost. As I warm up I start using only the one leg, and I put the otherfoot lower to help slightly and it also flexes that knee to a higherdegree. Also, when you come forward on the Kneeflexer, try to lift yourknee high on your toes; this moves the knee very effectively. The lastposition is about half way up the ramp and as I come forward I lift myknees as high as I can, going up on my toes. This also works on theflexion of the knee, just a little differently.

“I work on extension, first (foot at the top of the ramp). Then lowerthe foot on the ramp and work on flexion, find the place that pulls alittle after a short time, you will be able to lower the foot and havemore flexion. Now, move your foot up again and start working on liftingthe knee up and go on your toes at the top of your move forward. Iusually do each position for 5-10 minutes at a time, twice a day. Atnight I use the machine as I watch TV. I have used the machine two hoursstraight without much fatigue.

“The result has been nothing short of amazing. I now have full flexionand extension range in the knee, and I am once again highly effective asa karate instructor. My doctor cannot believe the rapid progress I havemade with the Kneeflexer.”

Although the preferred embodiment shows a curved motion mechanism(curved bearing rail) directly under the seat of the chair, what is mostimportant is that the center of rotation is up near the user's head;hence a curved motion mechanism could also be placed at the level of thebase, or it could be a revolute joint on a frame that extends from thebase to generally the level of the user's head. In addition, the bearingrail of the curved motion mechanism can be moving or fixed, attached tothe base or chair respectively, with the bearing carriage fixed ormoving accordingly. Alternately, the bearing rail could be replaced byother mechanisms providing generally the same motion; for example, atrolley system of wheels acting on a curved rail.

Further modifications of the invention will also occur to personsskilled in the art, and all such are deemed to fall within the spiritand scope of the invention as defined by the claims.

1. A moving seat chair comprising: a base, a curved motion mechanismwith generally between about 20-40 degrees of angular motion, a seat. 2.The moving seat chair of claim 1 where the curved motion mechanism iscomprised of: A bearing rail, a bearing carriage that moves on the rail3. The moving seat chair of claim 2 where the bearing rail is attachedto a structure mounted to the seat, and the bearing carriage is attachedto a post attached to the base.
 4. The moving seat chair of claim 2where the bearing carriage is attached to a structure mounted to theseat, and the bearing rail is attached to the base.
 5. The moving seatchair of claim 1 where the curved motion mechanism is comprised of oneor more individual curved sections.
 6. The moving seat chair of claim 1where the curved motion mechanism's radius of curvature is constant. 7.The moving seat chair of claim 1 where the curved motion mechanism'sradius of curvature varies.
 8. The moving seat chair of claim 1 withweight support structures, and weights on the weight support structure.9. The moving seat chair of claim 1 with springs generally attached tothe seat and to the base.
 10. The moving seat chair of claim 1 withdampers generally attached to the seat and to the base.
 11. The movingseat chair of claim 1 with a foot-support structure in front of thechair.
 12. The moving seat chair of claim 1 with an adjustable lengthstructure between the base and the chair.
 13. The moving seat chair ofclaim 1 with adjustable range of motion stops.
 14. A chair comprising aseat, a rail support structure, one or more curved bearing railsattached to the rail support structure, one or more bearing carriageswhich move on the curved rails, and a base frame that supports the chairabove the ground.
 15. The chair as claimed in claim 14 where thebearings are ball or roller element bearings.
 16. The chair as claimedin claim 14 where the bearings are sliding contact bearings.
 17. Thechair as claimed in claim 14 where the bearings are wheels which roll onthe curved rails.
 18. The chair as claimed in claim 14 with a ramp,stool, or step near the chair for the user to place their foot on toachieve different ranges of motion.
 19. The chair as claimed in claim 14with a brake to hold the chair in position while the user sits in it.20. The chair as claimed in claim 14 where the support frame isadjustable in height.